A conventionally liquid surface detecting apparatus was provided with: a float which floats on a liquid surface of a liquid; a holder rotatably held on a main body section; a cylindrical magnet fixed to this holder so as to be coaxial to a rotation axis of the holder; an arm which connects the float and the holder, and which converts an upward and downward movement of the float to a rotational motion of the holder; and a magnetic detecting element which is positioned at a substantial rotation center portion of the holder, and is fixed to the main body section, and which detects a magnetic change generated with displacement of the magnet and converts the change into an electrical signal and then output the converted electrical signal, the apparatus detecting the liquid surface on the basis of the electric signal from the detecting element (for example, refer to Patent Literature 1).